queries run twice unless 'parse statements' checked?

Running PostgreSQL 8.0, client is Visual Basic program using ADO, test case
has one adodc and a bound grid.

Queries involving a 188,000 row table were slow, even when query was on
single value in uniquely keyed index.

Turns out - from checking the plsqlodbc file, it was executing the query
once like I said:

select something from somewhere where thing=value

[returning one row]

then it ran the query again without the where clause [really!]

SELECT something FROM somewhere (The second query had the keywords turned
to upper case, if that helps identify what's going on.)

[returning 188,000 rows]

Naturally, this made things run slowly. I fiddled around and eventually
found that by checking "Parse Statements", this behavior stopped.

Anyway - is it supposed to work this way?

- Johann